Cross Connection Control

What is a Cross Connection?

A cross connection is a point in a plumbing system where the potable water supply is connected to a non-potable source. Briefly, a cross connection exists whenever the drinking water system is or could be connected to any non-potable source (plumbing fixture, equipment used in any plumbing system). Pollutants or contaminants can enter the safe drinking water system through uncontrolled cross connection when backflow occurs.

Cross Connection Control Survey

Under the provisions of the Safe Drinking Water Act of 1974, the Federal Government has established through the Environmental Protection Agency national standards of safe drinking water. In compliance with these regulations the City of Evanston adopted and enforces its own Cross Connection Control Program.

Please take a few minutes of your time to complete the survey answering all questions to the best of your ability.

*please note that this survey will be offered on a biennial basis (once every two years). A link to the survey will be posted again in 2017.

What is backflow and how likely is it to occur?

Backflow is the unwanted flow of non-potable substance back into the consumer’s plumbing system and/or public water system (i.e. drinking water).

There are two types of backflow: backsiphonage and backpressure. Backsiphonage is caused by a negative pressure in the supply line to a facility or plumbing fixture. Backsiphonage may occur during water main breaks, when repairs or maintenance are done on the water mains, when shutting off the water supply, when the fire department is using a fire hydrant, etc. Backpressure can occur when the potable water supply is connected to another system operated at a higher pressure or has the ability to create pressure. Principal causes are booster pumps, pressure vessels, and elevated plumbing.

How is the water supply protected from cross connections?

The best way to protect the water supply is to avoid having a cross connection in the first place! However, where a cross connection occurs, the use of backflow prevention devices can greatly decrease the risk of contamination.

Backflow prevention devices are mechanical devices designed to prevent backflow through cross connections. However, for backflow prevention devices to protect as designed, they must be installed in the right applications and meet stringent installation requirements.

What could happen if backflow prevention devices are not installed properly?

When backflow prevention devices are not installed properly, contamination of the drinking water supply can occur. Contaminants can be chemicals used in boilers, fire suppression or air conditioning systems such as ethylene glycol or chromium sodium dichromate. In lawn irrigation systems, chemicals used often include fertilizers, herbicides and pesticides. Bacteria from stagnant water, such as Legionnaire’s disease, are another potential contamination.

Often, people exposed to such contaminants may experience symptoms similar to intestinal viruses and may never realize the source. In other cases, the contaminants can cause serious long-term health problems, even resulting in fatality.

Before the City’s drinking water is compromised, the first people exposed to contaminants will be those who live or work in the buildings with backflow prevention devices.

What are the regulations?

The United States Government realized long ago the importance of protecting lakes, streams and rivers from pollutants. In 1948 Congress passed the “Federal Water Pollution Control Act”. They amended it in 1972 and again in 1977, renaming it the “Clean Water Act". The “Clean Water Act” enables the United States Environmental Protection Agency to enforce water quality and pollution control standards. Responsibility for enforcing these standards was then passed onto each individual state.

In Illinois, legislation was created to specifically state that water supply officials are responsible for protecting their water mains from connections that have the potential to allow the backflow of contaminants into their respective distribution systems. The City of Evanston is required by state law to enforce Illinois Environmental Protection Agency (IEPA) and the Illinois Department of Public Health (IDPH) rules and regulations governing this legislation, along with our own local code.